Process of removing gold, silver, copper, and platinum from lead alloys.



UITE STATES PATEN OIICE.

WILLIAM MORRISON, OF DES MOINES, IOWA.

PROCESS OF REMOVING GOLD, SILVER, COPPER, AND PLATINUM FROM LEAD ALLOYS.

Specification of Letters Patent.

Patented June 9, 1908.

Application filed April 18, 1907. Serial No. 368,892.

To all whom it may concern:

Be it known that I, VVILLIAM MORRISON, a citizen of the United States, residing at Des Moines, in the county of Polk and State of Iowa, have invented a certain new and use- 'ful Process of Removing Gold, Silver, Copper, and Platinum from Leadv Alloys, of which the following is a specification.

My object is to provide a process of this kind, especially adapted for removing gold or silver or copper or platinum from lead alloys, or for the direct refining of gold that is alloyed with silver and copper-or other alloys, and is more especially designed for use in cases where it is desirable to keep the several lots or quantities of alloys of said metals entirely separated. from each other, during the entire process.

A further object is to provide a process of this kind which may be quickly completed, so that the precious metals fromv the quantity of material presented may be removed and reduced to pure form within a few hours. In this connection, I am aware that there are good processes now in general use, for removing gold, silver, copper and platinum from alloys, which may be used advantageously when the amount of time employed in the final separation of the precious metals is not important.

My invention consists in the combination of the various steps of the process, whereby the objects contemplated are attained, as hereinafter more fully set forth and pointed out in my claims.

The means for combining gold, silver, copper and platinum with lead alloy from waste materials containing these metals, or any of them, is well known, and forms of itself no part of my present invention. I shall, there fore, in the following description refer only to the process for removing gold, silver, copper and platinum from a lead alloy, with these metals.

I place the lead alloy of precious metals in a crucible and add zinc and a suitable flux,

' such for instance as cyanid of potash, which I have found to be a desirable '[lUX for this purpose. I apply heat to the crucible until the contents of the crucible melts, and reaches a dull red heat.

It does not make any difference in the result, if the lead alloy of the precious metals is melted before adding the zinc and the flux,

the heat and agitation are applied to the material until the zinc approaches the point of volatilization. This volatilization of the Zinc may readily be determined by noting small yellow blazes rising through the flux. I preferably shut off the heat just before this volatilization begins, although no damage will result if only slight volatilization takes place,

and continue the agitation for a short time and then allow the crucible to cool slowly, so that the zinc and precious metals may separate from the lead and rise to the top. I then break the crucible, or before cooling it may be poured ofl? into another vessel previously heated.

The material thus treated will be in metallic form and the lead will be thoroughly separatedv from the other ingredients in a layer at the bottom of the vessel. This layer will be only slightly attached to the other material because the lead cools last and contracts and partially separates from the other material when cooling, so that the lead may, itdesired, be easily broken off or cut away from the other material. In this step of the process, it isnecessary that the material used for a flux shall be capable of melting at comparatively low temperature so that it will form a liquid and cover the other material before the zinc begins to volatilize, and for this reason I prefer to use cyanid of potash as a flux because, when in liquid form, and covering the other materials, it will take up any oxygen that may be present and form a potassium cyanate.

After the material has been treated as before described, and assuming that it is dethen melt the gold to reduce it to pure metallic form.

If it is desired to remove both the gold and platinum, I place the material in a vessel and add boiling concentrated sulfuric acid. This will dissolve the silver, zinc, copper and other impurities. wash the remaining material with hot water. I then remove the lead, if any is present, as before described, and separate the platinum and gold as follows: The material is placed in a suitable vessel and covered with a diluted solution of nitric muriatic acid, which will dissolve the gold and leave the platinum. As a substitute for the diluted solution of nitric muriatio acid, I have found that cyanid of potash, in solution, may be successfully used. In some instances I prefer to separate the platinum and gold as follows: I first place the platinum and gold in a suitable vessel and add a strong solution of nitric muriatic acid and apply heat. This causes both the metals to be dissolved. I then re duce the bulk of the solution by evaporation, and I then precipitate the platinum by adding a saturated solution of chlorid of ammonia in the presence of alcohol. The gold solution may then be poured off and the gold in turn recipitated with oxalic acid in solution, at oiling heat, or ferrous sulfate, or the like.

In cases where it is desired to save the gold, silver, copper and platinum, I first place the material in a suitable vesseland cover it with hydrochloric acid or diluted sulfuric acid. This will dissolve the zinc, leaving all the gold, silver, platinum and copper in powder or granular form, and the lead in metallic form. I then wash off the acid with the zinc. I then add just enough nitric acid to the residue to dissolve the copper and silver. I then precipitate the silver with hydrochloric acid, our off the solution and wash the residue and precipitate the copper with oXid of calcium. The platinum and gold are then separated as before described.

The advantage of this part of the process is that the zinc is first removed in the hydrochloric acid, hence there is only a small quantity of material remaining to be treated with nitric acid, and only a small quantity, just suflicient, is required to dissolve the cop per and silver. Then when the silver is precipitated with hydrochloric acid, the copper only remaining in the solution, which can be cheaply and directly precipitated by oXid of calcium when the other metals have been previously removed from the solution.

In some instances the lead alloy of gold may be treated. by melting it with zinc and without any cyanidof potash or other flux, then stirring and permitting it to slowly cool and separate. However, I prefer to use the flux as before described.

I then pour off the liquid and In cases where it is desired to use the proc ess in the direct refining of gold that is alloyed with the ordinary commercial alloys consisting of silver and copper, or any other alloys, I employ only that part of the process before described which consists in placing the material to be treated in a crucible, applying heat and adding zinc and cyanid of potash, which will result as before explained, in com bining Zinc with the gold and the alloying metals, so that the acid herein described may be applied to the material thus treated, anddissolve all but the gold. By this means gold that is alloyed with silver and copper or other materials, may be reduced to pure form in a comparatively short time, and it is obviously not necessary to first alloy the ma terial with lead.

. I am aware that other metals may be used as a substitute for the Zinc in the process as operate to dissolve all of the material except the gold.

In the following claims I have employed the term Zinc to indicate either pure Zinc or some metal that will have an equivalent action when treated in the manner herein described.

I claim as my invention 1. The process of separating gold from alloys, which consists in melting the same, in combination with zinc, and a material that will melt and form a flux before the zinc volatilizles, and then permitting the material to coo 2. The process of separating gold from alloys, which consists in melting the same in combination with zinc and a material that will melt and form a flux before the Zinc volatilizes, then agitating the material and permitting it to cool.

3. The process of separating gold from the same, in combination with zinc and a material that will melt and form a fluX at a tem-- perature lower than the volatilizing point of the zinc, and then permitting it to cool.

4. The process of separating gold from lead alloys of gold, which consists in melting the same, in combination with zinc and a material that will melt and form a flux at a temperature lower than the volatilizing point of the zinc, then agitating it and permitting it to cool.

5. The process gof separating gold from lead alloys of gold, which consists in melting the same in combination with Zinc and cyanid of potash, and then permitting it to cool.

6. The process of separating gold from lead alloys of gold, which consists in melting the same in combination with Zinc and cyanid of potash, agitating the same and permitting it to cool.

7. The process of separating gold from lead alloys of gold, which consists in melting the same, in combination with Zinc and a material that will melt and form a flux at a temperature lower than the volatilizing point of the zinc, then agitating it and permitting it to slowly cool, together with the heated. vessel in which it is contained.

S. The process of separating gold from lead alloys of the precious metals, which con-- sists in melting the same in combination with materials that will separate the precious metals from the lead, then adding to the separating material and the precious metals, a material that will dissolve all of the separating material and leave the precious metals.

9. The process of separating gold from lead alloys of the precious metals, which consists in ilirst melting the same and adding materials that will separate the precious metals from the lead, then adding to the separating material and the precious metals, a material that will dissolve all of the separating material and leave the precious metals, and then separating the precious metals.

10. The process of separating gold and platinum. from lead alloys of the precious metals, which consists in melting the same in combination with materials that will separate the precious metals from the lead, then adding to the precious metals and the separating material, a material that will dissolve the separating material and some of the precious metals, leaving the gold and plati num, and then separating the gold and. platinum.

11.. The process of separating gold from lead alloys of gold, which consists in melting the same in combination with materials that will separate the precious metals from the lead, then removing the lead, then adding a material that will dissolve the separating material and leave the gold, then washing the gold, and then melting it to metallic form.

12. The process of separating gold. from lead alloys of the precious metals, which consists in melting the same in combination with a material that will separate the precious metals from the lead, then dissolving the separating material and all of the other materials except the gold and the lead in strong nitric acid, then removing the lead, then washing the gold and melting it to reduce it to metallic form.

13. The process of separating gold from lead alloys of the precious metals, which consists in melting the same in combination with materials that will separate the precious metals from the lead, then adding an'acid that will dissolve silver, zinc, copper and the like, and leave both the gold and platinum, then washing the residue, then treating it with a material that will dissolve the gold, and then adding a material that will precipitate the gold.

14. The process of separating gold from lead alloys, of the precious metals, which con sists in melting the same in. combination with materials that will separate the precious metals from the lead, then adding boiling concentrated sulfuric acid, then pouring oil the liquid, then washing the residue with hot water, then adding a diluted solution of nitric muriatic acid, then pouring oil the liquid, and then precipitating the gold in the liquid.

15. The process of separating gold from lead alloys of the precious metals, which consists in melting the same in combination with materials that will separate the precious metals from the lead, then adding boiling concentrated sulfuric acid, then pouring off the liquid, then washing the residue with hot water, then adding a diluted solution of nitric muriatic acid, then. pouring oil' the liquid, an d then precipitating the gold in the liquid with heated oxalic acid.

16. The process of separating gold from lead. alloys of the precious metals, which consists in melting the same in combination with materials that will separate the precious metals from the lead, then adding boiling concentrated sulfuric acid, then pouring oil the liquid, then washing the residue with hot water, then adding to the residue a diluted solution of nitric muriatic acid, then pouring oil the liquid, then precipitating the gold in the liquid with heated oxalic acid, then precipitating the platinum by adding a saturating solution of chlorid of ammonia in the presence of alcohol.

17. The process of separating gold from lead alloys of the precious metals, which. consists in melting the same in combination with materials that will separate the precious metals from the lead, then adding a material that will dissolve the zinc and leave the gold, silver, platinum, copper and the like, in powder or granular form, then washing oil the acid, then. adding nitric acid. to dissolve the copper, and silver, then precipitating the silver with hydrochloric acid, and finally precipitating the copper with oXid of calcium.

18. The process of separating gold from lead. alloys, of gold, which consists in melting the same in combination with zinc, and a material that will melt and form a fluX before the zinc volatilizes, and then permitting the material to cool, then adding to the separatingmaterial and the precious metals, amaterial that Will dissolve all of the separating material and leave the precious metals, and then separating the precious metals.

19. The process of separating gold from lead alloys of gold, which consists in melting the same, in combination with zinc and a material that will melt and form a flux at a temperature lower than the volatilizing point of the zinc, then agitating it and permitting it to cool, then adding to the separating material and the precious metals, a material that will dissolve all of the separating material and leave the precious metals, and then separating the precious metals.

20. The process of separating gold from lead alloys of gold, which consists in melting the same in combination with zinc and cyanid of potash, and then permitting it to cool, then adding to the separating material and the precious metals a material that will dissolve all of the separating material and leave the precious metals, and then separating the precious metals.

2]. The process of separating gold from lead alloys of gold, which consists in melting the same in combination with Zinc and a material that will melt and form a flux before the Zinc volatilizes, then agitating the material and permitting it to slowly cool, together with the heated vessel in which it is con tained, then adding to the separating material and the precious metals, a material that will dissolve all of the separating material and leave the precious metals, and then separatingthe precious metals.

22. The process of separating gold. from lead alloys of gold, which consists in melting the same, in combination with zinc and a ma terial that will melt and form a flux at a temperature lower than the volatilizing point of the zinc, and then permitting it to slowly cool, together with the heated vessel in which it is contained, then adding to the separating material and the precious metals a material lead alloys of gold, which consists in melting the same in combination with zinc and cyanid of potash, and then permitting it to slowly cool, together with the heated vessel in which it is contained, then adding to the separating material and the precious metals, a material that will dissolve all of the separating material and leave the precious metals, and. then separating the precious metals.

24. The process of separating gold from lead alloys of gold, which consists in melting the same in combination with Zinc and cyanid of potash, and then permitting it to slowly cool, together with the heated vessel in which it is contained, then adding to the separating material and the precious metals, a material that will dissolve all of the separating material and leave the precious metals, and then separating the precious metals.

WILLIAM MORRISON l/Vitnesses RALPH Onwre. S. F. CHRISTY. 

